The present invention is an improvement in rock drill feed mechanisms of the type which may be extended to accommodate sectional drill steels of one length for drilling relatively long holes and then collapsed or telescoped for using shorter drill steels for drilling in confined areas. Examples of the advantageous use of such feed mechanisms would include drilling a drift or heading at an angle with respect to an existing drift or tunnel, or using the same feed mechanism for drift and stope drilling or roof bolting operations.
Prior art extendable or telescoping feed mechanisms are somewhat cumbersome and unstable when fully extended. Furthermore, it is desirable to achieve as much compactness and reliability in such mechanisms due to the confined operating area and the severe loads and punishment which must be withstood by rock drill feed apparatus. Examples of prior art extendable or telescoping feed mechanisms are disclosed in U.S. Pat. Nos. 3,744,574 and 3,807,510.
The present invention is considered to be an improvement in the art of extendable rock drill feeds in the above respects as well as others which will be appreciated by those skilled in the art.